As cold and flu season approaches, many people turn to supplements for immune system support. However, choosing supplements based on your specific health needs is essential rather than following general advice.

A food-first approach to nutrition is key. However, supplements may help fill gaps, especially during peak illness season. Some experts recommend Vitamin C and zinc as immune-boosting supplements.

What Science Says

Taking immune-boosting supplements is touted as a way to strengthen one’s body’s ability to fight off an infection rather than avoid sickness altogether.

“No product to date has been scientifically proven to prevent an infection. At most, what can be reasonably expected from these products is shortened duration and/or severity of cold symptoms,” Sevak Olmessekian, PharmD, a pharmacist at UCLA Health, told Verywell.

Vitamin C and zinc are two science-backed supplements that may help boost your immune system.

“Some studies have found that taking vitamin C before the start of cold symptoms, in other words prophylactically, may shorten how long the symptoms last,” Olmessekian said. Similarly, “some studies have suggested that zinc could reduce the duration of common cold symptoms but has little effect on preventing a cold,” he added.

Benefits of Vitamin C

Vitamin C is a potent antioxidant with the following properties:

• Neutralizes free radicals in your body
• Reduces oxidative stress
• Bolsters your immune system
• Speeds up healing
• May lower chronic disease risk (ex., cancer, heart disease)

As mentioned, research suggests vitamin C supplements may reduce the duration and severity of cold symptoms in specific groups of people. However, more research is needed.

Benefits of Zinc

Zinc is also a powerful antioxidant and has the following effects:

• Helps immune cell production
• Improves deficiency in sickle-cell disease
• May help prevent chronic diseases
• May increase blood sugar control in people with diabetes
• May improve skin health

Supplementing with zinc may help your immune system and reduce specific inflammatory markers. This is especially true if you are deficient in zinc.

Benefits of Taking Them Together

Taking vitamin C and zinc together may theoretically further bolster your immune system. However, the evidence is mixed.

Evaluate your current intake to understand any potential nutritional gaps:

• Vitamin C: Adults need between 75 and 90 milligrams (mg) of vitamin C daily. Taking more than 2,000 mg a day may cause side effects.
• Zinc: Adults need between 8 and 11 mg of zinc daily. Taking more than 40 mg a day may cause severe side effects.

Specific populations may experience a higher risk of deficiency and benefit from supplementation:

• Older adults
• People who smoke
• People with substance use disorders
• Individuals with limited food intake
• Those with absorption issues (e.g., gastrointestinal disorders)

Speak with your healthcare provider if you have concerns and whether you may benefit from taking vitamin C and zinc together.

Other Immune Boosting Supplements

• Vitamin D is another supplement that supports immune system function. Nearly half of the world’s population has vitamin D insufficiency. Those who don’t get enough of it may benefit from a supplement during cold and flu season, according to van der Merwe.
• Vitamin E may also play a role in keeping the immune system regulated, though you don’t necessarily need to take a supplement for it. It can be found in nuts, vegetable oils, seeds, green leafy vegetables, and fortified cereals, among other foods.
• Echinacea is another common cold remedy, though the evidence is mixed on whether it may work.